A separate lifting device is required when lifting loads of bricks stacked on pallets or other goods positioned in an easily collapsible stack on a platform. For reasons of safety at work in particular, this kind of lifting device has to be constructed so that it comprises not only a load carrying part, i.e. supporting means to be inserted under the pallet or platform, but also a wall, a grating, for instance, which is closed during lifting so as to surround the load on all sides in order to prevent the falling of the objects or products contained in the load during lifting. It is well-known to insert a lifting plate or alternatively a lifting fork under the pallet or platform of the stack of bricks, from which plate or fork a support arm projects above the stack of bricks so that a lifting hook acting as a coupling means is lifted substantially at its centre of gravity when loaded. This known arrangement further comprises a cage to be positioned around the stack of bricks, the front wall of the cage, that is, the wall on the side of the point portion of the lifting means, is openable about a vertical axis, so that when the door is open, the lifting device can be pushed so that the lifting means is positioned under the platform of the stack of bricks at the same time as the stack of bricks is positioned within the cage. After the door has been closed, the stack of bricks can be lifted by the lifting device. A drawback of this known arrangement is that the positioning of the stack of bricks always requires that the cage door should be opened, which required extra space and thus makes the work more difficult. Moreover, the entire lifting device has to be displaced in the transverse direction so as to insert the lifting means under the stack and to remove the lifting device so that it can be displaced to the following lifting stage. Still another drawback of the known lifting device is that the person handling it first has to go to one side of the device to open the door and then to the other side to push or pull the lifting device in position or to withdraw it.
DE Offenlegungsschrift 3 013 488 discloses a solution in which the lifting means itself and the support frame are similar to those of the device described above whereas the cage portion can be lifted and lowered in the direction of the height of the lifting device so as to make the device support the stack of bricks and to remove it from the device. These arrangements are rather heavy and as the person handling the device has to displace the entire device to the lifting point under the stack or away therefrom, the work is very strenuous. Furthermore, the cage structure is very complicated and cumbersome and expensive to manufacture.
U.S. Pat. No. 2,757,035 discloses an arrangement in which the lifting means are fixed to the frame pivotally with respect to it so that they can be inserted under the load and withdrawn, respectively, a spring force being applied to maintain them in both positions. This arrangement does not comprise any protective cage or protective framework and it cannot be used as such without a serious risk of injury. In addition, the solution is very complicated to manufacture.